This invention relates to a process for preparing various mono- and disubstituted mercaptophosphorothionochloridates.
The substituted mercaptophosphorothionochloridates are known compounds having utility as intermediates for the preparation of agricultural chemicals, such as insecticides and herbicides.
Various processes for preparing certain substituted mercaptophosphorothionochloridates have been described in the prior art. The following reaction schemes are typical of these processes: EQU P(S)Cl.sub.3 + RSH.fwdarw.RSP(S)Cl.sub.2 + HCl (1) EQU RSPCl.sub.2 + S.fwdarw.RSP(S)Cl.sub.2 ( 2)
These prior art processes are described in detail in Methoden Der Organischen Chemie, Band XII/1, Teil I pages 682-683 and 739-740 (1963) published by Georg Thieme Verlag, Stuttgart, Germany. While providing the desired compounds, these prior art processes have been found to be undesirable in that yields are often low and substantial amounts of undesirable by-products are formed.
U.S. Pat. No. 3,879,500 issued Apr. 22, 1975 to Eugene H. Uhing and Arthur D. F. Toy describes a process for preparing these compounds employing an appropriate chloride as a reactant, while U.S. Pat. No. 2,836,534 issued May 27, 1958 to Gail H. Birum teaches the preparation of some of the monosubstituted compounds from sulfenyl chloride and a phosphorus sulfide.